David McGrath

Using historical data to detect temporal changes in the abundances of intertidal species on Irish shores

An historical data set, collected in 1958 by Southward and Crisp, was used as a baseline for detecting change in the abundances of species in the rocky intertidal of Ireland. In 2003, the abundances of each of 27 species was assessed using the same methodologies (ACFOR [which stands for the categories: abundant, common, frequent, occasional and rare] abundance scales) at 63 shores examined in the historical study. Comparison of the ACFOR data over a 45-year period, between the historical survey and re-survey,showed statistically signi¢cant changes in the abundances of 12 of the 27 species examined. Two species(one classed as northern and one introduced) increased signi¢cantly in abundance while ten species (¢ve classed as northern, one classed as southern and four broadly distributed) decreased in abundance. The possible reasons for the changes in species abundances were assessed not only in the context of anthropogenic eiects, such as climate change and commercial exploitation, but also of operator error. The error or diierences recorded among operators (i.e. research scientists) when assessing species abundance using ACFOR categories was quanti¢ed on four shores. Signi¢cant change detected in three of the 12 species fell within the margin of operator error. This eiect of operator may have also contributed to the results of no change in the other 15 species between the two census periods. It was not possible to determine the eiect of operator on our results, which can increase the occurrence of a false positive (Type 1) or of a false negative (Type 2) outcome.

Effects of pingers on the behaviour of bottlenose dolphins

Trials were carried out in the Shannon estuary, Ireland, to test the effects of continuous (CPs) and responsive pingers (RPs) on bottlenose dolphin behaviour. In controlled trials, active and control pingers were deployed on fixed moorings, with T-PODs—acoustic monitoring devices to detect cetacean activity. In a separate trial, pingers were deployed from a moving boat which actively located dolphin groups in the estuary, and dolphin behaviour was recorded. In the static trials, overall detection rates of dolphin vocalizations on the T-POD were significantly lower in the presence of active CPs, but this was not the case for RPs. Mean inter-click interval values were longer for click trains produced in the presence of inactive RPs than for active RPs, active or inactive CPs. In boat-based trials, both active CPs and RPs appeared to affect bottlenose dolphin behaviour, whereby dolphins immediately left the area at speed and in a highly directional manner, involving frequent leaps.

Recruitment, immigration and population structure of two coexisting limpet species in mid-shore tidepools, on the west Coast of Ireland

Abstract Patellid limpets are common occupants of mid-shore tidepools on northern European shores, but their tidepool population structures have not been examined in detail. A series of mid-shore tidepools on Clare Island, Western Ireland were cleared of all Patella ulyssiponensis , Gmelin and P. vulgata L., in each of three years. A subset of these pools was subsequently recleared at monthly intervals, to determine juvenile recruitment to the pools and the rates of adult immigration. P. vulgata juveniles ( P. ulyssiponensis , but there was a steady decline of the P. vulgata recruits over time. The majority of limpets in the largest size class (>20 mm) were P. ulyssiponensis . No difference between the two species was observed in the immigration rates of the adults to the pools, but it is suggested that while P. ulyssiponensis remains in the pools, P. vulgata uses this microhabitat solely as a nursery ground, migrating from the pools as the animals increase in size, to give the observed pattern in population structure.

A revision of the North-east Atlantic species of Ericthonius (Crustacea: Amphipoda)

Seven species of the amphipod genus Ericthonius are described and figured from the North-east Atlantic and associated seas and a key to their identification is provided. West Atlantic material is also considered where relevant to the taxonomy of East Atlantic species. Two species are re-established after a long period of submersion in synonymy, and one species new to science is described. The previous confusion in the literature of some of the species is discussed, and a synonymy of species described in key works is provided.

Cetaceans in Irish waters: a review of recent research

To date, 24 cetacean species have been recorded in Irish waters. These are protected by a range of legislation, including the Whale Fisheries Act, the Wildlife Act and the EU Habitats Directive, which oblige Ireland to maintain cetacean populations and their habitat at a favourable conservation status. Policies aiming to maintain conservation objectives must be underpinned by scientifi c research. In this paper, we review historical and recent research on cetaceans in Irish waters (within the EEZ) to evaluate present knowledge and identify gaps in research. This information includes historical (pre-1976) records, targeted and incidental land, vessel and aerial based observations, acoustic surveys and monitoring and information from strandings. The habitat requirements of most cetacean species are not fully understood but some important habitats have been identifi ed. A number of threats to the welfare of cetaceans in Irish waters have also been identifi ed, including fi sheries interactions, pollution, climate change and disturbance. Future research required to fi ll gaps in knowledge highlighted by this manuscript is considered and discussed. Joanne O’Brien (corresponding author; email: joanne.obrien@gmit. ie); David McGrath, Department of Life Sciences, Galway– Mayo Institute of Technology, Dublin Road, Galway; Simon Berrow, Irish Whale and Dolphin Group, Merchants Quay, Kilrush, Co. Clare; Peter Evans, SeaWatch Foundation, 11 Jersey Road, Oxford 0X4 4RT, UK. Cite as follows: O’Brien, Joanne, Berrow, Simon, McGrath, David and Evans, Peter 2009 Cetaceans in Irish waters: A review of recent research. Biology and Environment: Proceedings of the Royal Irish Academy 109B, 63–88. DOI: 10.3318/ BIOE.2009.109.2.63. Received 13 December 2007. Accepted 29 October 2008. Published 30 July 2009. INTRODUCTION Irish coastal and offshore waters are some of the most important for cetaceans in Europe (Berrow 2001). Over the last two decades, there has been a rapid growth in our knowledge of the ecology of many cetacean species, due to an increase in research effort and the publication of literature. Numbers of cetacean-related publications have been consistently increasing since 1976 (Fig. 1). There has been an increase in national and international legal obligations for the protection of cetaceans and their habitats. Ireland has recently submitted the first conservation assessment of cetaceans under the EU Habitats Directive (NPWS 2008). For the 18 species (not including vagrants) that required an assessment, information on 12 of these species was reported as ‘unknown’, thus their conservation status could not be assessed. Ireland will be required to obtain sufficient information before the next reporting round of the Directive in 2013. In this paper, we review the current knowledge of cetacean ecology and research carried out to date in Irish waters. The overall aim of this review is to draw together all literature in a readily accessible format to identify information gaps and issues that should be addressed in the future, while contributing to the preparation of research and management plans. However, a detailed review and analysis of specific topics was beyond the scope of this paper. LEGISLATION There is a range of legislative instruments in Ireland aimed at protecting and managing cetaceans and their habitats. The first cetacean-related legislation enacted was the Whale Fisheries Act (1937) and associated Statutory Instruments, which required the licensing of all Irish-registered vessels engaged in whaling and banned the taking of (i) immature baleen whales (ii) female baleen whales accompanied by a calf, and (iii) all right whales. The conservation approach to whale and dolphin species was established with the Wildlife Act (1976) and Amendment (2000), which prohibited the hunting, injury, wilful interference and destruction of breeding places of cetaceans within the Exclusive Economic Zone (EEZ). The Government also issued guidelines to all boat operators in Ireland (Marine Notice no. 15, 2005) under a Statutory Instrument for correct procedures when encountering whales and dolphins, dictating inter alia that boats should not get closer than 100 metres and should maintain a speed of less than 7 knots. Ireland signed the Bern Convention on the Conservation of European Wildlife and Natural Habitats (1979), which offers protection to cetacean species. While this legally binding agreement did not extend the legal protection beyond that afforded by the Wildlife Act, it acted as a forerunner to more wide-ranging legislation. The protection of cetaceans was further extended Biology and Environment: Proceedings of the Royal Irish Academy, Vol. 109B, No. 2, 63–88 (2009).

Energy flow through an Amphiura filiformis (Ophiuroidea: Echinodermata) population in Galway Bay, west coast of Ireland: A preliminary investigation

Abstract The burrowing ophiuroid Amphiura filiformis (O.F. Muller) forms a stable, high density population in Galway Bay which is composed of one functional adult group containing many year classes. Recruitment rates are very low and annual somatic growth is almost entirely restricted to arm regeneration. The energy input to arm regeneration and to gonad production is estimated and respiration calculated from laboratory assays. Estimates of energy flow show that 77.4 % of energy is respired, 16 % goes to arm regeneration and 6.6% to gonad output. A P:B ratio of 1.97 is obtained for the Amphiura population and this is compared with values obtained in the literature for other echinoderms.

Verification of cyprid size as a tool in the identification of two European species of Chthamalus barnacles using mtDNA-RFLP analysis

Adult barnacles of Chthamalus stellatus and Chthamalus montagui were collected in August 1998, from Garrettstown Co. Cork and Kilkee Co. Clare, in southwest and west Ireland, respectively. Attached cypris larvae were collected during the settlement season of C. stellatus and C. montagui, on 2 shores in Co. Cork and 1 shore on Clare Island, Co. Mayo in west Ireland. Cyprid collections were made during either August or September, in 1992, 1994 and 1998 and all cyprids were measured along their carapace length. Size-frequency histograms were produced for each sampling occasion. Total DNA was extracted and the COI-COII mitochondrial genes were PCR amplified, both from selected adults and cyprids of each species collected in 1998. Composite haplotypes, produced by digesting PCR products with the restriction endonucleases TaqI and RsaI, showed clear identification between the 2 species as adults and larvae. Of the 68 cyprids examined, those measuring 525 μm and under were found to have RFLP profiles corresponding with C. montagui adults, while those of 550 μm and larger were found to match C. stellatus adults. The findings verify previous length-frequency analysis. Carapace length is an important character in the identification of C. stellatus and C. montagui cyprids. The PCR primers developed during this study will also amplify DNA from 4 other species of . acorn barnacle.

Reproduction, growth and feeding of the dragonet, Callionymus lyra (Teleostei: Callionymidae), in Galway Bay, Ireland

A Galway Bay population of the dragonet Callionymus lyra (L.) was investigated between March 1978 and November 1979. Monthly collections were made on board commercial fishing vessels. A total of 3302 fish was examined. The male to female sex ratio in the catch was 1·14:1 and it departed significantly from a 1:1 ratio. Males grew significantly faster than females, when measured by length and by weight, and attained a greater maximum length, but females had a longer life span. Females were significantly heavier than males for any body length. The spawning season was protracted, lasting from January to August and peaking during February-April. Callionymus lyra is a carnivore, feeding mainly on polychaetes and crustaceans, but molluscs and echinoderms were also eaten in abundance. A yearly cycle in feeding intensity was observed, showing reduced feeding during the colder months. The feeding index expressed as gut weight / body weight was significantly higher for females.

Prolonged settlement and prediction of recruitment in two sympatric intertidal Chthamalus species from south-west Ireland

Attached cypris larvae and less than one month old metamorphs of Chthamalus stellatus and C. montagui (Crustacea: Cirripedia) were sampled from random quadrats on two shores in County Cork, Ireland, from July 1996 to June 1997. Cyprids of C. stellatus were much more abundant than those of C. montagui , but the relative abundance of metamorphs of the two species did not differ significantly. Cyprid abundance predicted metamorph recruitment intensity during peak settlement in C. stellatus but not in C. montagui .

Social Structure Within the Bottlenose Dolphin (Tursiops truncatus) Population in the Shannon Estuary, Ireland

The Shannon Estuary is home to Ireland’s only known resident population of bottlenose dolphins (Tursiops truncatus) and is designated as a candidate Special Area of Conservation (cSAC) for this species. Proper conservation management of these dolphins requires an understanding of the social structure of this population. Four years of photoidentification data (2005 to 2009, excluding 2007) were used to construct sociograms that complement a cluster analysis of individually marked dolphins and their associates. The results found little evidence of social stability or group fidelity for this study’s dolphin population. Analysis of dolphins observed in consecutive years showed that the probability of group members encountering an individual dolphin in the second year did not depart from a random model. The social parameters for this resident population seem to be typical for this species. Bottlenose dolphins are found to exhibit a highly fluid, dynamic social structure within which individuals change their composition and associates regularly. These dolphins in the Shannon Estuary appear to live in a fission-fusion based society.